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SCREW THREADING MAGHINE.

Patented Jan. 9, 1883.

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Unrren STATES ATENT Farce,

NVILLIAM D. FORBES, OF BRIDGEPORT, CONNECTICUT, ASSIGNOR OF ONE- HALF TO RODERICK P. CURTIS, OF SAME PLACE.

SCREW-THREADING MACHINE.

SPECIFICATION forming part Of Letters Patent No. 270,409, dated January 9, I883.

Application filed July 24, 1882.

T 0 all whom it may concern Be it known that I, \VILLIAM D. FORBES, a citizen of the United States, and a resident ofBi-idgeport, Connecticut, have invented certain Improvements in Die-Stocks, of which the following is a specification.

My invention relates to certain improvements in the die-stock for which Letters Patent' of the United States No. 253,996 were granted to me on the 21st day of February, 1882, the main object of my present improvements being to readily vary the direction and pitch of the thread, and a further object being to insure accuracy in the cutting ofsaid thread.

It] the accompanying drawings, Figure l is a front View of my improved die-stock. Fig. 2,21, sectional plan view of the same on the line 1 L, and Fig. 3 a vertical section on the line 3 4.

A is the casing of the implement, which is bolted or otherwise secured to a work-bench, and has internal bearings for a t othed ring, B, and an elongated pinion, D, the latter being adapted to rotate the ring I without interfering with the longitudinal traversing of the same within the casing. The outer projecting portion of the hub aof the ring B has setscrews 1) for clamping to the ring a. pipe or rod upon which a thread is to be cut, and to the inner portion of the hubis secured, by setscrews d, a threaded ring, F, which constitutes a lead-screw, and is adapted to a nut, G, the latter fitting snugly to a recessed flange, f, on the casing A, andbeing prevented from moving longitudinally by. screws 9 passing through the flange and engaging with a shoulder at on the nut. The nut G is locked to the flangef by means of a screw-pin, h, adapted to an opening in the nut, and to a threaded opening in the casing, the withdrawal of said ptn leaving the nut free to revolve.

J is the cutting-die, which is adapted to guides n on the casing, and rests upon a lug, 1), so that it is incapable of either rotary or longitudinal movement.

The operation of the device is as follows: The parts being in the position shown in Fig. 2, and a pipe or rod being secured to the ring B, so that its end is in contact with the die J, as shown by dotted lines, the ring B is rotated by means ot the pinion, so that, owing to the lead-screw F and nut G, the said ring will be caused to move in the direction of the arrow, and the pipe will be thrust into the die, which cuts the desired thread thereon.

By using a fixed die and rotating audtraversing' the pipe a truer thread will be cut thereon thanit' the die was rotated and traversed, as defects in the centering ot' the pipe can be more easily detected when the pipe r0- tates than when it is stationary.

When it is desired to cut off the ragged or uneven end of a pipe a cutter may be inserted in place of the die J, and the nut Gr released frotn the flaugefby withdrawing the pin h, so that the ring B and the. pipe can be turned without any longitudinal movement being imparted thereto.

The detachable lead-screw F and nut G are important features of my invention, as they permit the use of the stock for the cutting of threads of vary ing pitch, and for cutting either right or left hand threads, one lead-screw and nut being removed and another substituted therefor when a change in the character of the thread to be cut becomes necessary.

I claim as my invention- 1. The cotnbination of the fixed casing A, carrying the die J, and having a nut, G, with the toothed pipeholding ring B, adapted to rotate and slide in the casing A, and having a leadingscrew adapted to the said nut, all substantially as set forth.

2. The combination of the casiugA, carrying the die J, and having a flange, f, the ring B, provided with a detachable feed-screw, F, the shouldered nut G, and set-screw 9, all substantially as set forth.

In testimony whereofI have signed my name to this specification in the presence of two subscribing witnesses.

VVlLLIAM I). FORBES.

Witnesses:

JAMES F. TOBIN, HARRY SMITH. 

